Tube joint and method of manufacturing same



, D 1'7,` 1935. F. w. scHwlNN 2,024,782

TUBE Joim: AND METHOD' or' MANUFACTURING SAME lFiled April 9, 1954 Patented Dec. 17, 1935 v UNITED STATES TUBE JOINT AND METHOD OF MANUFAC? TUBING SAME Frank W. Schwinn, Chicago, Ill.

Application April 9, 1934, Serial No. 719,767 24 claims. (o1. zia-148.2)

My invention relates to the constructing of frames, such as for example bicycle frames and fuselages of airplanes, comprising members, such as for example and more particularly tubular members, disposed in angular position relative to each other, one phase of my invention relating to the reinforcing of the joint and another phase to the joint itself. 4

One of my objects is to improve the means hitherto employed for the reinforcing purpose and to reduce to the minimum danger of impairment of .the frame under the stress of heavy loads and unusual shocks, and with the employment ofthe minimum of metal.

Another object is to provide a joint which, for.

reach bar and the steering head tube of a bicycle 'I frame of common shape,these partsv being joined together andthe upper reach bar reinforced, in

accordance with my invention, the section being taken at the line l on Fig. 2 and viewed in the direction of the arrow; andv Figure 2, a plan view, with certain parts sectioned, of the construction shown in Fig. 1, the

lsectionv being taken at the line 2 on liig.V 1 and -viewed-in the direction of the arrow.

In the exempliflcation of my invention as illus- Itrated, 3 represents-the upper end of the steering `head tube of a bicycle frame, andl'4 the top tubular bar thereof` which connects with the tube 3and the seat post tube (not shown).

. In accordance'with my invention as illustrated the end tube 4 at which it is to be joined to the 40 tube 3 is reinforced and the joint between these 'tubes produced, by first inserting into the end of the tube 4, usually of steel,'a short length of tube 5 of similar metal to project a short distance beyond the adjacent end of the tube 4 as shown at 6, the tube 5, which preferably is of approximately the same thickness as the tube 4, being provided of such diameter that it may be manually pushedfinto the tube 4 to the position above referred to and thus have what is commonly known/as a push fit with the tuber4.

The assembly of tubes 4 and 5 is then subjected to externally applied pressure, as for'exampley by cold swedging them, for circumferentlally constricting the tubes'4 and 5 in opposition to the resistance of the metal thereof to distortion, to reduce their diameters toward the end of the tube assembly 4, 5, at which the joint with the tube 3 is to be made.

In the particular construction shown the constricting of the tubes 4, 5 progressively increases 5 from the line indicated at 1` to the line indicated at 8, the tube assembly therebeyond and represented at 9 being of uniform diameter but constricted relative to the other part of the tube assembly. 10

`tube assembly would be about .985 outside diameter, would suiice. Furthermore, While a portion of the tube 5, and represented at l0, is shown 20 I' as in normal, unconstricted, condition, this is not necessary as the constricting of the"tubes 4,r 5

may be initiated atthe innerextremity of the tube 5 in which case the tube 5 would terminate at the line 25 The end of the tube 5 at winchthe joint is to be made with thetube 3l is so shaped, as

shown, as to conformingiy t the side orthe tube 3 and the adjacent end'of the tube l which extends short of the tube 3 is correspondingly 30 shaped. Thus when the tube assembly 45:1` is applied to the tube 3 a. continuous groove Il is presentedbetween the tubes 3 andV 4.

The tube 3, and tube assembly 4, 5Zhavingr been assembled to the position they are to nally 35 occupy, they are permanently secured together, as for example and preferably, by welding them with a welding rod the metal of which is run into the groove I l as shown at I2 forming a ring weld and thus rxnly uniting the tubes 4 and 5 40 together and to the tube 3.

As will be understood from the foregoing, the resistance to bending of the assembly 4, 5, which is at the maximum at its portion of greatest constriction, gradually decreases in intensity from 45 the line 8 to the line-1 at which latter location no constriction exists andthus the tube 4 will not be subjected to such a bending moment as` would tend to break it at this point.,

While I have illustrated and described a par- 50 ticular embodimentof my invention and have described a certain method of procedure in the practicing of my improved method, I do not Wish ,t to be understood as intending to limit it thereto as the structure shown may be variously modl- 55 iied and altered and my improved method practiced in other ways without departing from the 4reinforced a reinforcing tube andy subjecting the assembled tubes to external pressure over an axially extending area, in opposition to the resistance of the metal of the tubes to deformation, for reducing the diameters of both tubes toward an end thereof.

2. The method of producing a reinforced tube which consists in inserting into the tube to be reinforced to have push-fit therewith, a reinforcing tube and subjecting the assembled tubes to external, attenuating pressure over an axially extending area, in opposition to the resistance .of the metal of the tubes to deformation.

3. The method of producing a reinforced tube which consists in inserting into the tube to be reinforced a reinforcing tube and swedging the assembled tubes to attenuate an end portion of the assembly over an axially extending area, in opposition to the resistance of the metal of the tubes to deformation, for reducing the diameters of both tubes toward an end thereof.

4. The method of producing a reinforced tube which consist-s in inserting into the tube to be reinforced a reinforcing tube and subjecting the.

assembled tubes to external, attenuating pressure over an axially extending area,in opposition to the resistance of the metal of the tubes to deformation, for reducing the normal diameters of both tubes toward an end thereof.

5. In the method of producing a tubeA joint, the steps which consist in inserting intothe tube to be reinforced a reinforcing tube and subject-1` ing the assembled tubes to external-pressure, in opposition to the resistance of the metal of the tubes to deformation, for gradually reducing the diameters of-both tubes towardan end thereof. 6.V In the method of producing 'a tubev jointthe steps which consist in inserting into the tube v to be reinforced a reinforcing tube vand subject?v ing the assembled tubes to external pressure, in vopposition to the resistance of the metal of they tubes; to deformation.k for gradually' reducing the diameters of bothy tubes'toward an end'thereof and --therebeyond reducing 'the tubes to j uniform diameter.

7. A tube assemblyjcomprising a mainftube- 'l jand a 'reinforcing thereinthroughoutf'a cylinder, said -tubes beingconstricted,l against' the; resistance` of the metal of the tubesto dis-- tortion, adjacentthe endl Aof the assembly at' whichit is to bev joined to another-member.

8. A.A tube assembly comprising a main tubeV and-'areinforcing tube therein over an axially extending area said tubes being gradually con' whichcomprise inserting a reinforcing tube into stricted, against the resistance of the metal of the tubes to distortion, toward the end of the assembly at whichl it is to be joined to another-V member.

9. A tube assembly comprising' a main .tube

tion, toward the end of the assembly at which it is to be joined to another member, the constriction of the reinforcing tube extending from a portion thereof which remains of normal 'diameter.

' tubes and members together. v 14. A. tube-joint comprising `members one of f lwhichxis'a tube to be connected with the other of said members-at a side of the 'latter,'and a re- `inforcing tube-insaid mst-referred-totube pro# Y jectingbeyond .the adjacent end ofthe latter at 45 the joint, wherebyagioove.ispresented'between an end ofsaid flrst-referredsto' tube and said'4 other member, said tubesand memberfbeingconf Vnected together by a weld at saidgroove. 15. lA'tubejoint comprising members one. of 50 whichis aftube tobe connected with the other of said members at a-sideof the latter, and a rein" forcing tube' in said 'first-referrecl-to tube pro'-,

and a reinforcing tube therein, said tubes being 10 jointly constricted at an end portion, against the resistance of the metal of the tubes to distortion, said constriction gradually4 decreasing from a point between the ends of said portion in a direction away from the adjacent end of the assembly, 15 and the constriction of the reinforcing tube extending from a portion thereof which remains of normal diameter.

12. A tube-joint comprising members one of which is a tube to be connected with the other of 30 said members at a side of the latter, a reinforcing tube in said rst-referred-to tube projecting beyond the adjacent end of the latter at the joint, whereby a groove is presented between an end of said rst-referred-to tube and said other 25 member, and bonding material fused into said groove and connecting said tubes and member together.

13. A tube-joint comprising members one of which is a tube to be connected with the other 3:) of said members at a side of the latter, a yreinforcing tube in saidiirst-referred-to tube projecting throughout-its circumference beyond the adjacent end of said first-referred-to tube at the joint, wherebya continuous groove.y is pre- 35 sented betweenjan end of said first-referred-to vtube and said other member, andbonding material fused into saldgroove throughoutthe circumference ofthe latter and connecting said jecting throughout its circumference beyond the adj acent end of said ilrstfreferrede'tov'tube at lthe 55 joint, wherebyl *aj continuous groove lis presented between anendof -said i's't-refe'rred-to tube and said other member, saidtubes and .member beinErv connected together by an annular weld at saidgroove. Y '.60 Y 16. Inthe production'of a tube joint, the steps the tube ytovbe reinforced and subjecting the as-V sembled-tubes to external pressure adjacent an endther'eof, over a' substantial portion of their'5 extent vparallel `with their axes and uniformly -Y l about the circumference of said portion to reduce the diameters of-both tubes against the resistance ofthe vmetal of the tubes to deformation.

'- 17; In'the production of a tube joint, the steps 7o' rcomprise inserting a reinforcing tube into an end the circumference of the tubes, said pressure gradually varying along said extent whereby to reduce the diameters of said portions of both tubes, the reduction oi' ,diameters gradually lessening in amount in a direction away from said end.

18. A tube assembly comprising a main tube and a reinforcing tube therein, said tubes being so reduced in diameter from their normal dimensions over an axial cylinder toward en end of the assembly at which it is to be joined to another member, as to provide great frictional cohesion between the tubes.

19. A tube assembly comprising a main tube, a l

reinforcing tube therein terminating at a location spaced from an end of the main tube, and

- means producing relatively great frictional cohesion between the tubes adjacent said end and relatively slight frictional cohesion at said termination of the reinforcing tube.

20. A tube assembly comprising a main-tube, a reinforcing tube therein terminating at a location-spaced from an end of the main tube, and means producing relatively great frictional cohesion between the tubes adjacent said end and relatively slight frictional cohesion at said termination of the reinforcing tube, said frictional cohesion gradually lessening from an area of great cohesion as the said termination is approached.

21. A tube assembly comprising a main tube having an attenuated portion of reduced diameter, a reinforcing tube in said portion extending from an end of the main tube and terminating at a location spaced from said end, means to positively prevent movement between the ends oi' said tubes and means providing frictional cohesion between said tubes adjacent said ends. 5

22. A tube joint comprising a tubular member,

a tube assembly secured toa side of said member, said assembly comprising a tube and a reinforcing tube therein and projecting therefrom to contact said side of said member whereby to provide a groove between the end of said rst named tube and said side, the securing means comprising bonding material fused into said groove to immovably secure the ends of said assembly together and to said side,'means to prof 15 vide relatively great cohesion between the tubes of said assembly adjacent their ends and relatively slight cohesion therebetween at a location spaced from said ends.

23. In a tube joint assembly, a main tube, a reinforcing tube in said main tube, adjacent ends of said tubes from a location intermediate the ends of the tube joint assembly being of decreased diameters toward one end of the tube assembly, one of said tubes projecting beyond the other tube at the latter end.

24. In a tube jointassembly, a main tube, a reinforcing tube in said main tube, the adjacent ends of said tubes beinglof decreased diameters toward an end of the tube assembly, one of said tubes projecting beyond the other tube at said end, and a weld connecting the tubes at said end.

FRANK W. SCHWINN. 

